Most poisonous creature
could be a mystery insect
Q:
What is
the most poisonous creature on Earth? D. Bertovic, Dubrovnik,
Croatia
A:
Colombia, South America. Midday,
in the depths of a jungle west of the Andes along a Pacific river. It is
dark, hot, and dismal. Dusk never leaves the day below the tree canopy.
Rainwater pools in huge, still leaves. A heavy atmosphere clings to the
earth like a coiling miasma.![[Charles W Myers, American Museum of Natural History] The extremely toxic P. terribilis, who eats pure poison](http://www.wonderquest.com/2002-06-07-p-terribilis.jpg)
The extremely toxic P. terribilis,
who eats pure poison. Photo courtesy of Charles W Myers, American
Museum of Natural History
"Thwoop," breaks the silence
as a poison dart hurtles from a blowgun to its target: a howler monkey
secure on a lower branch of a tree towering a hundred feet above the rain
forest floor. The dart penetrates the monkey's reddish fur, into her flesh
and bloodstream. She falls, paralyzed, unable to breathe, and her heart
fails.
The poison from the skin of
the world's most poisonous known creature-the tiny, 1.5-inch, Golden Poison
Frog (Phyllobates terribilis)-kills the monkey.
An average P. terribilis
contains about one milligram of poison, which is enough to kill 10,000
mice-perhaps enough to kill 10 to 20 humans if the poison reaches their
bloodstreams.
This extraordinarily lethal
poison (a steroid alkaloid, called batrachotoxin) almost does not occur in
nature. We have found this poison only among three poison frogs in Colombia
and two poison birds in Papua, New Guinea.
The yellow frog stores the
poison in skin glands, as do most frogs. Due to their poison, frogs taste
awful to predators but P. terribilis' poison kills whatever eats it-except
for a snake (Liophis epinephelus). This snake is resistant to the frog's
poison but not immune.
"We fed one juvenile frog to
a snake and the snake showed great distress and was rendered helpless for
several hours," says John Daly, chief of the National Health Institute's
bioorganic chemistry laboratory.
The poison frogs are perhaps
the only creatures immune to this poison. The poison attacks the sodium
channels of the cells. Through the ages, the clever frog has evolved special
sodium channels that the poison can not harm.
Frogs normally have no
occasion to eat their own poison but this frog is different. The frog
apparently eats the same poison as his own but produced by some OTHER
CREATURE. He eats the unknown creatures as we might eat shrimp or chicken:
just standard food. Frogs grown in captivity, however, can't eat the same
food and they are NOT poisonous. "All evidence indicates that such frogs
obtain the poisons unchanged from some creature in their diet," says Daly.
"Thus, the high toxicity of
P. terribilis appears due to consumption of an unknown mysterious small
insect or other arthropod, which may truly be the most poisonous creature on
Earth. It is a mystery that we hope to someday solve."
(Answered Jun. 7, 2002, Updated June 12, 2009)
Further Reading:
Most poisonous creature update: mystery solved, WonderQuest
J.W. Daly, "Thirty years of
discovering arthropod alkaloids in amphibian skin." J. Natural Products
61:162-172, 1998.
C.W. Myers, J.W. Daly, and B.
Malkin, 1978, "A dangerously toxic new frog (Phyllobates) used by the Emberá
Indians of western Colombia, with discussion of blowgun fabrication and dart
poisoning." (Bulletin of the American Museum of natural history, vol. 161,
article 2, pp. 307 - 365 + color pls. 1 - 2).
International Wildlife
Encyclopedia edited by Maurice and Robert Burton, 1969.
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